STRAIGHTEN UP - Natural Awakenings

consciouseating
liQuiD
nutRition
Water Myths
and truths
by Catherine guthrie
For the past 50 years, nutritionists
and other health experts have
been exhorting Americans to
drink more water. If the ubiquity of
water bottles is anything to go by,
the message has been received loud
and clear. But now, updated research
lets us off the hook. It turns out that
much of the water craze springs from
a deep well of misinformation. Our
experts debunk some of the most
popular water myths.
MYTH: You need eight, eight-ounce
glasses of water a day to be healthy.
TRUTH: The familiar eight-by-eight
rule is likely based on misinterpretation,
rather than scientific certainty,
says Dr. Heinz Valtin, a kidney specialist, textbook author
and retired professor at Dartmouth Medical School, in
Hanover, New Hampshire. Valtin traces the prescription to
a 1945 recommendation by the Food and Nutrition Board
of the National Research Council to take in, “1 milliliter for
each calorie of food.”
In a study published in the American Journal of Physiology
in 2002, Valtin explains that most of that allotment already
comes from the foods we eat. He not only discredits the need
for most people to consume this “mythical” amount of water
every day, but writes that the recommendation is potentially
harmful, by making people feel guilty for not drinking
enough.
“The consumer ended up thinking only plain water
counts,” says Ann Grandjean, Ph.D., a hydration researcher
and medical nutritionist with the University of Nebraska
Medical Center, in Omaha. But almost all liquids—including
tea, coffee and beer—count toward the daily water intake,
she says.
So, how much should you be drinking? Researchers at
the National Academy of Sciences’ Institute of Medicine,
after reviewing more than 400 studies, including Valtin’s, set
the general daily intake for women and men at about 91 and
125 ounces, respectively. The average American receives 20
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percent of this daily water intake from food. The remaining
80 percent comes from all beverages—not just water.
MYTH: Caffeinated beverages zap the body’s water reserves.
TRUTH: Grandjean first became interested in the reputed
link between dehydration and caffeine while working as
a consultant to the United States Olympic Committee. “I
worked with elite athletes, and I noticed they drank a lot of
caffeinated beverages without showing any sign of dehydration,”
she says. In 2000, she published a study in the Journal
of the American College of Nutrition showing that the body
doesn’t discriminate between regular and decaf beverages
when it comes to hydration.
MYTH: If you’re thirsty, you’re already dehydrated.
TRUTH: While thirst is an accurate barometer of when to
imbibe, the notion that thirst signals a dehydrated body is not
true, says Valtin. Thirst is triggered when the blood’s concentration
of solid particles rises by 2 percent. Dehydration
occurs when the blood concentration rises by 5 percent. So,
thirst sets in before dehydration and people who shrug off
their thirst can find themselves on the path to dehydration.
“Thirst is the first indicator of the body’s need for water,”
cautions Dee Sandquist, a spokesperson for the American Dietetic
Association. Signs to watch out for include headache,
dry mouth, rapid pulse and lightheadedness.
MYTH: Urine should be clear.
TRUTH: Perpetually clear urine can actually be a sign of
drinking too much water, which can dilute the body’s electrolytes,
according to Grandjean. “Healthy urine should have
some color,” she counsels. Certain vitamins, such as riboflavin
(B ), can darken urine.
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MYTH: Drinking a lot of water suppresses the appetite.
TRUTH: While being adequately hydrated helps the metabolism
run at its optimal level, drinking vast quantities of water
won’t affect the overall amount of food you eat. Because
water quickly empties from the stomach, drinking water has
little effect on appetite, says Barbara Rolls, director of the
Laboratory for the Study of Human Ingestive Behavior, at
Pennsylvania State University. Eating foods that have a high
water content, such as fruits, vegetables, soups and grains,
can help us to feel sated.
MYTH: Bottled water is always better than tap water.
TRUTH: Not necessarily. Be aware that bottled water is often
just tap water. A Natural Resources Defense Council report
cites government and industry findings that 25 percent of
bottled water is plain tap water; sometimes treated, sometimes
not. NSF International certification indicates brands
that meet federal safety standards.
Catherine Guthrie is an award-winning health and lifestyles
journalist in Bloomington, IN. Connect at CatherineGuthrie.com.